Abstract: BACKGROUND: The detection rate of hypertension in children and adolescents has increased in recent years, which is a public health problem worthy of attention. At present, there is no research on the prevalence and influencing factors of hypertension among children and adolescents in Hainan Province. Early hypertension in children and adolescents has no obvious clinical symptoms and is not easy to be found.
OBJECTIVE: To investigate the prevalence, distribution characteristics and influencing factors of hypertension among school students aged 6-18 years in Hainan Province, so as to provide a theoretical basis for early and precise prevention and intervention.
METHODS: The health monitoring data of school students in 18 cities and counties in Hainan Province from 2013 to 2020 were collected. A total of 6 253 567 pieces of information were included, including 3 408 734 (54.51%) pieces of information for boys and 2 844 833 (45.49%) pieces of information for girls. The Blood Pressure Reference Standards for Sex, Age and Height of Chinese Children Aged 3-17 Years, the 2018 Revised Guidelines for Prevention and Treatment of Hypertension in China, Screening Cut-Off Values for Overweight and Obesity in School-Aged Children and Adolescents WS_ T586-2018, High Waist Circumference Screening Cut-Off Values for Children and Adolescents Aged 7 To 18 Years WS_T611-2018, and Comprehensive Evaluation of the Developmental Level of Children and Adolescents were used to detect blood pressure of children and adolescents aged 6-17 years, blood pressure, body mass index, waist circumference and spirometry index of adolescents aged 18 years. Whether to be abdominal obesity adopts the international recommended criteria, that is, the waist circumference and height ratio ≥ 0.5 is abdominal obesity. Spearman analysis and multinomial logistic regression analysis were used to analyze the correlation between body mass index, waist circumference, waist-to-height ratio, spirometry index and blood pressure and the risk factors.
RESULTS AND CONCLUSION: The distribution of hypertension in school students aged 6-18 years in Hainan Province has the following characteristics: (1) The distribution of hypertension in children and adolescents has regional clustering, and the severity of blood pressure from high to low is in the south, east, west, center, and north. (2) There were significant differences in the degree of hypertension between boys and girls at different ages (P < 0.001). The detection rate of elevated blood pressure in boys after 13 years of age increased significantly than that in girls. The detection rate of stage 1 hypertension in boys increased significantly after 14 years of age. The severity of blood pressure in girls aged 6-13 years was higher than that in boys, and the severity of blood pressure in boys aged 14-17 years was higher than that in girls. (3) Multivariate logistic regression analysis results showed that female students [odds ratio (OR)=1.185, 95% confidence interval (CI): 1.180-1.189, P < 0.001], body mass index (overweight OR=1.144, 95% CI: 1.135-1.154, P < 0.001; obesity OR=1.120, 95% CI: 1.105-1.135, P < 0.001), waist circumference (high normal waist circumference OR=1.053, 95% CI: 1.046-1.061, P < 0.001; high waist circumference OR=1.025, 95% CI: 1.012-1.037, P < 0.001) and waist-to-height ratio (OR=1.286, 95% CI: 1.270-1.303, P < 0.001) were risk factors for hypertension in children and adolescents. Age, spiro-index (middle level: OR=0.956, 95% CI: 0.944-0.968, P < 0.001); middle and upper level: OR=0.869, 95% CI: 0.8588-0.880, P < 0.001; first-class level: OR=0.739, 95% CI: 0.726-0.753, P < 0.001) were protective factors for hypertension in children and adolescents. A higher spirometry index level indicated a lower risk of hypertension in children and adolescents. (4) The above data indicate that the detection rate of hypertension in school students aged 6-18 years is relatively high in Hainan province. Region, year, age, sex, body mass index, waist circumference, abdominal obesity, and spirometry index are all influencing factors for the detection rate of hypertension in children and adolescents. Body mass index, waist circumference and waist-to-height ratio should be controlled within the normal range in children and adolescents aged 6-18 years. Increasing spirometry index levels is an important tool for blood pressure control in children and adolescents. 

Key words: Hainan Province, children and adolescents, hypertension, detection rate, influencing factor, body mass index, waist circumference, waist-to-height ratio, spirometry index